The recovery of used frying oils with various adsorbents

The recovery of used frying oils is of commercial and economic importance. One additional reuse of recovered oil could provide considerable savings to the food processors. Seven commonly used filter aids: Silasorb, Britesorb, HE 600, Purifry, Frypowder, Activated Carbon, and Magnesol, as well as two commercially unavailable adsorbents, Sorbead AF and Calsilite were studied. A number of AOCS official methods were used to evaluate their adsorptiveness, fee fatty acids (FFA), conjugated diene value (CDV), total polar components (TPC), oxidative stability index (OSI), color and viscosity (V). High performance size exclusion chromatography was employed to determine the amount of polymers and low molecular weight compounds. When heated to 150C prior to filtration, HE 600 was found to reduce FFA content by 84.5%. Frypowder improved oil stability by 38. 3%, and Magnesol lightened oil color by 46. 3%. After statistical analysis of the data, five of them were selected, two or three of which were blended to obtain the most effective combination. The blending of HB 600 and Magnesol reduced FFA and TPC by 90.8-93.7% and 6.0-17.8%, respectively, and improved oil stability by 23.4-24.7%. The adsorbent combinations have potential for use in practical frying operation to improve the functional and healthy aspects of used frying oils.